Mahmoud Elewa | Alexandria University (original) (raw)
Papers by Mahmoud Elewa
Separation and Purification Technology
Nanomaterials
Water shortage is a major worldwide issue. Filtration using genuine polymeric membranes demonstra... more Water shortage is a major worldwide issue. Filtration using genuine polymeric membranes demonstrates excellent pollutant separation capabilities; however, polymeric membranes have restricted uses. Nanocomposite membranes, which are produced by integrating nanofillers into polymeric membrane matrices, may increase filtration. Carbon-based nanoparticles and metal/metal oxide nanoparticles have received the greatest attention. We evaluate the antifouling and permeability performance of nanocomposite membranes and their physical and chemical characteristics and compare nanocomposite membranes to bare membranes. Because of the antibacterial characteristics of nanoparticles and the decreased roughness of the membrane, nanocomposite membranes often have greater antifouling properties. They also have better permeability because of the increased porosity and narrower pore size distribution caused by nanofillers. The concentration of nanofillers affects membrane performance, and the appropria...
Water
The scarcity of drinkable water supplies is becoming a serious and troubling challenge to long-te... more The scarcity of drinkable water supplies is becoming a serious and troubling challenge to long-term development. This issue emphasises the urgency of implementing rapid water desalination options. However, desalination is a capital-intensive process that requires a significant amount of energy, and since it is now mostly powered by fossil fuels across the globe, it has the potential to leave a significant carbon footprint. In this light, transitioning to green energy sources for desalination is a necessity in today’s society. Humidification–dehumidification (HD) is one of the most effective desalination procedures to consider for distant places with modest fresh water demands for household and agricultural demands. This is mostly because it requires minimal operational and maintenance concerns. The current article examines the many kinds of HD desalination systems driven by solar energy sources and their key components. The current study established that the seawater HD system is vi...
Water, 2022
Humidification–dehumidification (HD) is a non-traditional desalination process in which water eva... more Humidification–dehumidification (HD) is a non-traditional desalination process in which water evaporates from a saline liquid stream and the vapour condenses into purified water. In nature, seawater is heated by solar radiation and evaporates from the air that moistens it. This is known as the rainy cycle. The artificial version of this cycle is called the HD desalination cycle. The latter has received a lot of attention in recent years, and many researchers have studied the complexities of the technology. In the present work, experimental work with a simple configuration was developed and built, consisting of a humidification column followed by a condenser, in which the humidified air is dehumidified to produce fresh water. A novel and unique packaging material was used in the humidifier, consisting of a cellulose plant grown on the banks of the River Nile. In all previous work, the main problem was the type of packaging material that could ensure intimate contact and uniformity be...
Molecules, 2022
Dyes are a major class of organic pollutants that are well-known for their harmful impact on aqua... more Dyes are a major class of organic pollutants that are well-known for their harmful impact on aquatic life and humans. Several new strategies for removing colours from industrial and residential effluents have recently emerged, with adsorption being the best option. The current study looked at the recovery of direct dyes from aqueous streams for reuse using macro-reticular ion exchange resins (IERs). The investigation includes dyeing single jersey cotton grey textiles with direct dyes from the Isma dye Company in Kafr El Dawar, Egypt. After centrifuging and separating the supernatant liquid, solutions from thirteen different dyes, produced at an average concentration between the wasted and soaping liquor concentrations, were calculated spectrophotometrically from the first dyeing trials. Kinetic data were well fitted with pseudo-second-order rate kinetics. The amounts of dye retained by the anion exchangers increased with a rise in temperature in the case of Strong Base Resin (SBR) a...
Separations, 2021
This review investigates antifouling agents used in the process of membrane separation (MS), in r... more This review investigates antifouling agents used in the process of membrane separation (MS), in reverse osmosis (RO), ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), membrane distillation (MD), and membrane bioreactors (MBR), and clarifies the fouling mechanism. Membrane fouling is an incomplete substance formed on the membrane surface, which will quickly reduce the permeation flux and damage the membrane. Foulant is colloidal matter: organic matter (humic acid, protein, carbohydrate, nano/microplastics), inorganic matter (clay such as potassium montmorillonite, silica salt, metal oxide, etc.), and biological matter (viruses, bacteria and microorganisms adhering to the surface of the membrane in the case of nutrients) The stability and performance of the tested nanometric membranes, as well as the mitigation of pollution assisted by electricity and the cleaning and repair of membranes, are reported. Physical, chemical, physico-chemical, and biological methods for cl...
DESALINATION AND WATER TREATMENT, 2017
Silver nanoparticles (Ag-NPs) play an important role in the electronic industry, whereas, Zeroval... more Silver nanoparticles (Ag-NPs) play an important role in the electronic industry, whereas, Zerovalent iron (ZVI) has been widely investigated for environmental remediation due to its fairly strong reducing power and its ability to adsorb an array of important contaminants such as heavy metals and metalloids, while, chitosan nanoparticles (CS-NPs) have proven efficacy in removal of heavy metals, dyes and phenols from wastewater. In the present work, chemical methods have been conducted to prepare nanoparticles made from silver, iron, and chitosan. Ag-NPs were prepared from AgNO 3 as starting material then the particles obtained were coated on filter paper; also, a cellulose acetate (CA) membrane was prepared after mixing the casting solution with Ag-NPs, then both subjected to Escherichia (E.) coli bacteria for testing their ability to destroy the bacteria. The E. coli was prepared according to a standard procedure and the colonies counted before and after treatment with treated filter paper and membrane. It is noteworthy that the present work contains a simple new method to prepare Ag-NPs. Results proved that Ag-NPs destroy the E. coli bacteria completely at room temperature in both filter paper and CA membrane. Also, Nano iron (nZVI) was prepared by reduction of ferric chloride by sodium borohydride, then filtered and used to remove Cu(II) ions from aqueous solution. CS-NPs were prepared by two methods, first by preparation of low molecular weight chitosan (LWCS) followed by its degradation to CS-NPs using different concentrations of H 2 O 2 solution. The second method was done by preparing CS-NPs using AgNO 3. The CS-NPs membrane was able to biosorb 70.68 and 42.1% of NaCl from a 9.38 and 15.2 g/L salt solution respectively, whereas biosorption of CuSO 4 was 59.8% from 12.5 g/L solution, due to the presence of numerous functional groups besides the amino and hydroxyl groups.
DESALINATION AND WATER TREATMENT, 2017
Desalination of saline waters by freezing is one of the oldest methods for desalination, which re... more Desalination of saline waters by freezing is one of the oldest methods for desalination, which relies on the principle that the ice crystal structure cannot accommodate salts during its formation, and salts are rejected during phase transformation. Despite its numerous merits as compared to thermal desalination processes, such as low energy requirements, minimum corrosion potential and no scale formation on surfaces, and its suitability for remote areas, small societies, and cold regions, yet it has been neglected during the last few decades. In the present work, an investigation was conducted to determine the effect of directional freezing on the salinity of the produced ice. Containers of different configurations and sizes, which were filled with saline water of different initial concentrations, were subjected to gradual freezing, then sliced into several equal sections from top to bottom, and the ice allowed to melt in separate containers, while other configurations were sliced into circular annular sections of different radii, then all the samples were analyzed for NaCl. Variables studied for their effect on the salinity, included container configuration, initial saline concentration (C i) (5, 15, 25 and 35 g/L), and vertical/radial distances. It was found that concentration increased from periphery to center and from top to bottom. The freezing and solubility curves of NaCl-water system were calculated using the perturbed-chain statistical associating fluid theory (PC-SAFT) with the corresponding melting temperatures and enthalpies of fusion of the pure substances using the binary parameter (k ij) of-0.1793 for NaCl-water system.
DESALINATION AND WATER TREATMENT, 2017
In the present work, a prototype was devised and constructed as a preliminary step for the develo... more In the present work, a prototype was devised and constructed as a preliminary step for the development of industrial scale process in which desalination by an emulsion liquid membrane (ELM) technique takes place. The process is intended to be a breakthrough in the field of desalination, which should compete with the currently used reverse osmosis (RO) technique. A drawback of RO is the high cost of membrane and intensive pretreatment of seawater. The prototype consists of three stages: emulsion formation, desalination operation, and separation of the product into two phases (desalinated water and spent emulsion). The latter could be then adjusted and recycled for reuse in a second cycle. Several investigated factors which could affect the desalination process were: initial concentration (Ci), volume ratio of liquid membrane (LM) to receptor phase (RP), quantity of emulsifier, type of liquid membrane, type and quantity of sequestering agent (SA), time and power of ultrasonication (US), presence of mobile carrier (MC) and finally treatment ratio (ratio of volumes of donor phase (DP) to emulsion) (TR). The best conditions arrived at were: volume ratio of LM:RP = 4:1, necessary in forming a stable emulsion. The optimum quantity of MC was found to be 6.86 g Span 80 for 80 ml chlorobenzene and 20 ml 20% soluble starch, so that best transfer of the NaCl could take place from DP to RP. Soluble starch (2% b.w.) is a suitable sequestrant for NaCl, chlorobenzene was better than chloroform, the latter is better than Soltrol 220 as LM. It was also found that 5 min at 180 Watts of US to provide a stable emulsion. The quantity of emulsifier and Ci are of crucial importance that affects directly the desalination process.
Desalination and Water Treatment, 2016
AbstractScarcity of potable water nowadays, presents a serious problem all over the world. Enviro... more AbstractScarcity of potable water nowadays, presents a serious problem all over the world. Environmental changes are taking place at a rapid pace, resulting in greenhouse effects, desertification, and lack of fresh water. Accordingly, scientists are working hard toward inventing new techniques for desalinating sea water, which presents the only alternative solution to this problem. In this regard, desalination techniques are mainly divided into thermal and membrane techniques. However, the latter are superior in that they are modular in shape, and consume less energy. In the present work, desalination by a novel recent membrane separation technique, the so-called sweeping air pervaporation (PV), which has been very sparsely applied to desalination of sea water, has been conducted in our laboratory. The technique is simple, straightforward, cost-effective and does not suffer from limitations as regards low water recovery, such as reverse osmosis. An innovated deacetylated cellulose acetate (CA) membrane wa...
Desalination and Water Treatment, 2016
AbstractIn the present work, the removal of NaCl using the present type of supported liquid membr... more AbstractIn the present work, the removal of NaCl using the present type of supported liquid membrane technique has been investigated. A simple apparatus devised and constructed was used to conduct the experiments. Various factors that would affect the progress of transport were studied and these were initial concentration (Ci) of simulated seawater in donor phase (DP), presence of mobile carrier (MC) in the liquid membrane (LM), concentration of MC in LM, presence of sequestering agent (SA) in the receptor phase (RP), and speed of stirring. The volume ratio of DP to RP was kept constant at 2:1. Type (1,2 dichloroethane (DCE)) and thickness (2 mm) of LM were kept constant. Cellophane constituted the support for the LM. The most important findings emphasized the importance of the presence of a MC in the LM to enhance mass transfer through the LM and that an optimum concentration of MC existed. Also the importance of stirring in promoting mass transfer by minimizing the boundary layer intact to the cellophan...
Desalination and Water Treatment, 2015
AbstractMany industries, such as tanning, metal processing, electroplating, etc., include copper ... more AbstractMany industries, such as tanning, metal processing, electroplating, etc., include copper in their processes and discharge it in wastewater streams. The permissible limit of copper in wastewater is 1.3 mg/L, accordingly, industries must lower their copper limits to meet their local legal guidelines. This can be done by numerous methods including chemical precipitation, oxidation–reduction, ion exchange, etc. Electrocoagulation (EC)/floatation (ECF) technique, however, is an effective, cheap and simple electrochemical method for treating wastewater containing copper (Cu(II)) ions, which involves generation of coagulants using sacrificial electrodes when a DC voltage is applied; simultaneously generating hydrogen gas at the cathode which can help in the floatation of the formed particles. In the present work, a specially devised and innovated bench-scale EC apparatus was constructed and used in the removal of Cu(II) ions from aqueous solution. Numerous factors were investigated for their effect on th...
Water Practice & Technology, 2015
Ultrafiltration (UF) has received tremendous attention in concentration and purification of prote... more Ultrafiltration (UF) has received tremendous attention in concentration and purification of proteins in biotechnology, biomedicine and food production industries. Accordingly, in the present work innovated super-hydrophilic UF membranes were fabricated by the phase inversion technique, from a special casting solution formulation consisting of cellulose acetate in different solvents/additives, followed by complete deacetylation to form a regenerated cellulose membrane. Variables investigated included time of evaporation of as-cast membrane, temperature of coagulation water bath and post annealing of membrane. The membranes were used in ultrafiltrating yeast suspensions and examined by scanning electron microscopy (SEM), Fourier transform infrared, contact angle, porosity and pore size. The membrane performance was found to be strongly affected by each variable, and the best membrane gave a consistently high flux (27 kg/m2h) on prolonged operation, with almost zero salt rejection (%SR...
Environmental Technology, 2015
In the present work, removal of NaCl using the bulk liquid membrane (BLM) technique has been inve... more In the present work, removal of NaCl using the bulk liquid membrane (BLM) technique has been investigated, using a simple apparatus for conducting the experiments. Variables investigated were volume ratio of donor phase (DP) to receptor phase (RP), presence of sequestering agent (SA) in RP, type of organic liquid membrane (LM), quantity of mobile carrier (MC) in the LM. Stirring speed and volume of LM were kept constant at 100 rpm and 130 ml, respectively. The mass transfer of NaCl was analysed based on kinetic laws of two consecutive irreversible first-order reactions, and kinetic parameters (k1d, k2m, k2r, [Formula: see text], tmax, [Formula: see text], and [Formula: see text]) for the transport of NaCl were investigated. The values obtained demonstrate that the process is diffusionally controlled. Results indicate that the membrane entrance and exit rate constants (k1, k2) increase with decreasing DP:RP ratio and with decrease in quantity of MC, and quantity of SA, and the presence of dichloroethane (DCE) is preferred to chloroform (CF) as LM.
Desalination and Water Treatment, 2013
Desalination using liquid membranes (LMs) has been investigated in our laboratory using emulsion,... more Desalination using liquid membranes (LMs) has been investigated in our laboratory using emulsion, supported and flowing LMs. However, bulk liquid membranes (BLMs) have not yet been applied as is clear from the literature cited. Accordingly, in the present work, the aforementioned technique was investigated for removal of sodium chloride from solutions of different concentrations as an attempt for desalination. Variables investigated included: type and quantity of LM, quantity of mobile carrier (MC) in LM, and type and quantity of sequestering agent in receptor phase (RP). Results indicated that: a mixture of 1:1 b.v. dichloroethane (DCE) plus chlorobenzene (CB) was a better LM than CB alone, and that DCE was almost equivalent to nitrobenzene (NB). As to the effect of sequestering agent, soluble starch gave better complexation with NaCl than sorbitol in the RP. It was also shown that the presence of the selected MC was efficient. An optimum quantity of MC led to the highest percentage of extraction of NaCl. The smaller volume of LM leads to higher extraction due to shorter diffusion path of the complex of NaCl plus MC through the LM. The highest extraction obtained was about 75%.
Sustainability
Solar radiation is considered the main renewable energy source which reshapes the global sustaina... more Solar radiation is considered the main renewable energy source which reshapes the global sustainability plan for future development. Due to the lack of solar radiation measurements, this work investigates the performance of several temperature-based hybrid solar radiation models combining the parametric, statistical and satellite data approaches to estimate the global solar radiation on a horizontal surface. Over 35 years of meteorological data in the new location, Arar City, KSA (Latitude 30°96′ N and longitude 41°05′ E) are employed to establish and validate the models. These models are validated using two datasets with different averaging time spans to investigate the accuracy and reliability of different models as forecasting tools for the solar radiation. The mostly common statistical indicators are calculated to identify the most accurate model. The results show that Model (1) has the best performance among all models with high reliability as a solar radiation forecasting tool...
Water
Due to the impacts of water scarcity, the world is looking at all possible solutions for decreasi... more Due to the impacts of water scarcity, the world is looking at all possible solutions for decreasing the over-exploitation of finite freshwater resources. Wastewater is one of the most reliable and accessible water supplies. As the population expands, so do industrial, agricultural, and household operations in order to meet man’s enormous demands. These operations generate huge amounts of wastewater, which may be recovered and used for a variety of reasons. Conventional wastewater treatment techniques have had some success in treating effluents for discharge throughout the years. However, advances in wastewater treatment techniques are required to make treated wastewater suitable for industrial, agricultural, and household use. Diverse techniques for removing heavy metal ions from various water and wastewater sources have been described. These treatments can be categorized as adsorption, membrane, chemical, or electric. Membrane technology has been developed as a popular alternative ...
Case Studies in Thermal Engineering
Separation and Purification Technology
Nanomaterials
Water shortage is a major worldwide issue. Filtration using genuine polymeric membranes demonstra... more Water shortage is a major worldwide issue. Filtration using genuine polymeric membranes demonstrates excellent pollutant separation capabilities; however, polymeric membranes have restricted uses. Nanocomposite membranes, which are produced by integrating nanofillers into polymeric membrane matrices, may increase filtration. Carbon-based nanoparticles and metal/metal oxide nanoparticles have received the greatest attention. We evaluate the antifouling and permeability performance of nanocomposite membranes and their physical and chemical characteristics and compare nanocomposite membranes to bare membranes. Because of the antibacterial characteristics of nanoparticles and the decreased roughness of the membrane, nanocomposite membranes often have greater antifouling properties. They also have better permeability because of the increased porosity and narrower pore size distribution caused by nanofillers. The concentration of nanofillers affects membrane performance, and the appropria...
Water
The scarcity of drinkable water supplies is becoming a serious and troubling challenge to long-te... more The scarcity of drinkable water supplies is becoming a serious and troubling challenge to long-term development. This issue emphasises the urgency of implementing rapid water desalination options. However, desalination is a capital-intensive process that requires a significant amount of energy, and since it is now mostly powered by fossil fuels across the globe, it has the potential to leave a significant carbon footprint. In this light, transitioning to green energy sources for desalination is a necessity in today’s society. Humidification–dehumidification (HD) is one of the most effective desalination procedures to consider for distant places with modest fresh water demands for household and agricultural demands. This is mostly because it requires minimal operational and maintenance concerns. The current article examines the many kinds of HD desalination systems driven by solar energy sources and their key components. The current study established that the seawater HD system is vi...
Water, 2022
Humidification–dehumidification (HD) is a non-traditional desalination process in which water eva... more Humidification–dehumidification (HD) is a non-traditional desalination process in which water evaporates from a saline liquid stream and the vapour condenses into purified water. In nature, seawater is heated by solar radiation and evaporates from the air that moistens it. This is known as the rainy cycle. The artificial version of this cycle is called the HD desalination cycle. The latter has received a lot of attention in recent years, and many researchers have studied the complexities of the technology. In the present work, experimental work with a simple configuration was developed and built, consisting of a humidification column followed by a condenser, in which the humidified air is dehumidified to produce fresh water. A novel and unique packaging material was used in the humidifier, consisting of a cellulose plant grown on the banks of the River Nile. In all previous work, the main problem was the type of packaging material that could ensure intimate contact and uniformity be...
Molecules, 2022
Dyes are a major class of organic pollutants that are well-known for their harmful impact on aqua... more Dyes are a major class of organic pollutants that are well-known for their harmful impact on aquatic life and humans. Several new strategies for removing colours from industrial and residential effluents have recently emerged, with adsorption being the best option. The current study looked at the recovery of direct dyes from aqueous streams for reuse using macro-reticular ion exchange resins (IERs). The investigation includes dyeing single jersey cotton grey textiles with direct dyes from the Isma dye Company in Kafr El Dawar, Egypt. After centrifuging and separating the supernatant liquid, solutions from thirteen different dyes, produced at an average concentration between the wasted and soaping liquor concentrations, were calculated spectrophotometrically from the first dyeing trials. Kinetic data were well fitted with pseudo-second-order rate kinetics. The amounts of dye retained by the anion exchangers increased with a rise in temperature in the case of Strong Base Resin (SBR) a...
Separations, 2021
This review investigates antifouling agents used in the process of membrane separation (MS), in r... more This review investigates antifouling agents used in the process of membrane separation (MS), in reverse osmosis (RO), ultrafiltration (UF), nanofiltration (NF), microfiltration (MF), membrane distillation (MD), and membrane bioreactors (MBR), and clarifies the fouling mechanism. Membrane fouling is an incomplete substance formed on the membrane surface, which will quickly reduce the permeation flux and damage the membrane. Foulant is colloidal matter: organic matter (humic acid, protein, carbohydrate, nano/microplastics), inorganic matter (clay such as potassium montmorillonite, silica salt, metal oxide, etc.), and biological matter (viruses, bacteria and microorganisms adhering to the surface of the membrane in the case of nutrients) The stability and performance of the tested nanometric membranes, as well as the mitigation of pollution assisted by electricity and the cleaning and repair of membranes, are reported. Physical, chemical, physico-chemical, and biological methods for cl...
DESALINATION AND WATER TREATMENT, 2017
Silver nanoparticles (Ag-NPs) play an important role in the electronic industry, whereas, Zeroval... more Silver nanoparticles (Ag-NPs) play an important role in the electronic industry, whereas, Zerovalent iron (ZVI) has been widely investigated for environmental remediation due to its fairly strong reducing power and its ability to adsorb an array of important contaminants such as heavy metals and metalloids, while, chitosan nanoparticles (CS-NPs) have proven efficacy in removal of heavy metals, dyes and phenols from wastewater. In the present work, chemical methods have been conducted to prepare nanoparticles made from silver, iron, and chitosan. Ag-NPs were prepared from AgNO 3 as starting material then the particles obtained were coated on filter paper; also, a cellulose acetate (CA) membrane was prepared after mixing the casting solution with Ag-NPs, then both subjected to Escherichia (E.) coli bacteria for testing their ability to destroy the bacteria. The E. coli was prepared according to a standard procedure and the colonies counted before and after treatment with treated filter paper and membrane. It is noteworthy that the present work contains a simple new method to prepare Ag-NPs. Results proved that Ag-NPs destroy the E. coli bacteria completely at room temperature in both filter paper and CA membrane. Also, Nano iron (nZVI) was prepared by reduction of ferric chloride by sodium borohydride, then filtered and used to remove Cu(II) ions from aqueous solution. CS-NPs were prepared by two methods, first by preparation of low molecular weight chitosan (LWCS) followed by its degradation to CS-NPs using different concentrations of H 2 O 2 solution. The second method was done by preparing CS-NPs using AgNO 3. The CS-NPs membrane was able to biosorb 70.68 and 42.1% of NaCl from a 9.38 and 15.2 g/L salt solution respectively, whereas biosorption of CuSO 4 was 59.8% from 12.5 g/L solution, due to the presence of numerous functional groups besides the amino and hydroxyl groups.
DESALINATION AND WATER TREATMENT, 2017
Desalination of saline waters by freezing is one of the oldest methods for desalination, which re... more Desalination of saline waters by freezing is one of the oldest methods for desalination, which relies on the principle that the ice crystal structure cannot accommodate salts during its formation, and salts are rejected during phase transformation. Despite its numerous merits as compared to thermal desalination processes, such as low energy requirements, minimum corrosion potential and no scale formation on surfaces, and its suitability for remote areas, small societies, and cold regions, yet it has been neglected during the last few decades. In the present work, an investigation was conducted to determine the effect of directional freezing on the salinity of the produced ice. Containers of different configurations and sizes, which were filled with saline water of different initial concentrations, were subjected to gradual freezing, then sliced into several equal sections from top to bottom, and the ice allowed to melt in separate containers, while other configurations were sliced into circular annular sections of different radii, then all the samples were analyzed for NaCl. Variables studied for their effect on the salinity, included container configuration, initial saline concentration (C i) (5, 15, 25 and 35 g/L), and vertical/radial distances. It was found that concentration increased from periphery to center and from top to bottom. The freezing and solubility curves of NaCl-water system were calculated using the perturbed-chain statistical associating fluid theory (PC-SAFT) with the corresponding melting temperatures and enthalpies of fusion of the pure substances using the binary parameter (k ij) of-0.1793 for NaCl-water system.
DESALINATION AND WATER TREATMENT, 2017
In the present work, a prototype was devised and constructed as a preliminary step for the develo... more In the present work, a prototype was devised and constructed as a preliminary step for the development of industrial scale process in which desalination by an emulsion liquid membrane (ELM) technique takes place. The process is intended to be a breakthrough in the field of desalination, which should compete with the currently used reverse osmosis (RO) technique. A drawback of RO is the high cost of membrane and intensive pretreatment of seawater. The prototype consists of three stages: emulsion formation, desalination operation, and separation of the product into two phases (desalinated water and spent emulsion). The latter could be then adjusted and recycled for reuse in a second cycle. Several investigated factors which could affect the desalination process were: initial concentration (Ci), volume ratio of liquid membrane (LM) to receptor phase (RP), quantity of emulsifier, type of liquid membrane, type and quantity of sequestering agent (SA), time and power of ultrasonication (US), presence of mobile carrier (MC) and finally treatment ratio (ratio of volumes of donor phase (DP) to emulsion) (TR). The best conditions arrived at were: volume ratio of LM:RP = 4:1, necessary in forming a stable emulsion. The optimum quantity of MC was found to be 6.86 g Span 80 for 80 ml chlorobenzene and 20 ml 20% soluble starch, so that best transfer of the NaCl could take place from DP to RP. Soluble starch (2% b.w.) is a suitable sequestrant for NaCl, chlorobenzene was better than chloroform, the latter is better than Soltrol 220 as LM. It was also found that 5 min at 180 Watts of US to provide a stable emulsion. The quantity of emulsifier and Ci are of crucial importance that affects directly the desalination process.
Desalination and Water Treatment, 2016
AbstractScarcity of potable water nowadays, presents a serious problem all over the world. Enviro... more AbstractScarcity of potable water nowadays, presents a serious problem all over the world. Environmental changes are taking place at a rapid pace, resulting in greenhouse effects, desertification, and lack of fresh water. Accordingly, scientists are working hard toward inventing new techniques for desalinating sea water, which presents the only alternative solution to this problem. In this regard, desalination techniques are mainly divided into thermal and membrane techniques. However, the latter are superior in that they are modular in shape, and consume less energy. In the present work, desalination by a novel recent membrane separation technique, the so-called sweeping air pervaporation (PV), which has been very sparsely applied to desalination of sea water, has been conducted in our laboratory. The technique is simple, straightforward, cost-effective and does not suffer from limitations as regards low water recovery, such as reverse osmosis. An innovated deacetylated cellulose acetate (CA) membrane wa...
Desalination and Water Treatment, 2016
AbstractIn the present work, the removal of NaCl using the present type of supported liquid membr... more AbstractIn the present work, the removal of NaCl using the present type of supported liquid membrane technique has been investigated. A simple apparatus devised and constructed was used to conduct the experiments. Various factors that would affect the progress of transport were studied and these were initial concentration (Ci) of simulated seawater in donor phase (DP), presence of mobile carrier (MC) in the liquid membrane (LM), concentration of MC in LM, presence of sequestering agent (SA) in the receptor phase (RP), and speed of stirring. The volume ratio of DP to RP was kept constant at 2:1. Type (1,2 dichloroethane (DCE)) and thickness (2 mm) of LM were kept constant. Cellophane constituted the support for the LM. The most important findings emphasized the importance of the presence of a MC in the LM to enhance mass transfer through the LM and that an optimum concentration of MC existed. Also the importance of stirring in promoting mass transfer by minimizing the boundary layer intact to the cellophan...
Desalination and Water Treatment, 2015
AbstractMany industries, such as tanning, metal processing, electroplating, etc., include copper ... more AbstractMany industries, such as tanning, metal processing, electroplating, etc., include copper in their processes and discharge it in wastewater streams. The permissible limit of copper in wastewater is 1.3 mg/L, accordingly, industries must lower their copper limits to meet their local legal guidelines. This can be done by numerous methods including chemical precipitation, oxidation–reduction, ion exchange, etc. Electrocoagulation (EC)/floatation (ECF) technique, however, is an effective, cheap and simple electrochemical method for treating wastewater containing copper (Cu(II)) ions, which involves generation of coagulants using sacrificial electrodes when a DC voltage is applied; simultaneously generating hydrogen gas at the cathode which can help in the floatation of the formed particles. In the present work, a specially devised and innovated bench-scale EC apparatus was constructed and used in the removal of Cu(II) ions from aqueous solution. Numerous factors were investigated for their effect on th...
Water Practice & Technology, 2015
Ultrafiltration (UF) has received tremendous attention in concentration and purification of prote... more Ultrafiltration (UF) has received tremendous attention in concentration and purification of proteins in biotechnology, biomedicine and food production industries. Accordingly, in the present work innovated super-hydrophilic UF membranes were fabricated by the phase inversion technique, from a special casting solution formulation consisting of cellulose acetate in different solvents/additives, followed by complete deacetylation to form a regenerated cellulose membrane. Variables investigated included time of evaporation of as-cast membrane, temperature of coagulation water bath and post annealing of membrane. The membranes were used in ultrafiltrating yeast suspensions and examined by scanning electron microscopy (SEM), Fourier transform infrared, contact angle, porosity and pore size. The membrane performance was found to be strongly affected by each variable, and the best membrane gave a consistently high flux (27 kg/m2h) on prolonged operation, with almost zero salt rejection (%SR...
Environmental Technology, 2015
In the present work, removal of NaCl using the bulk liquid membrane (BLM) technique has been inve... more In the present work, removal of NaCl using the bulk liquid membrane (BLM) technique has been investigated, using a simple apparatus for conducting the experiments. Variables investigated were volume ratio of donor phase (DP) to receptor phase (RP), presence of sequestering agent (SA) in RP, type of organic liquid membrane (LM), quantity of mobile carrier (MC) in the LM. Stirring speed and volume of LM were kept constant at 100 rpm and 130 ml, respectively. The mass transfer of NaCl was analysed based on kinetic laws of two consecutive irreversible first-order reactions, and kinetic parameters (k1d, k2m, k2r, [Formula: see text], tmax, [Formula: see text], and [Formula: see text]) for the transport of NaCl were investigated. The values obtained demonstrate that the process is diffusionally controlled. Results indicate that the membrane entrance and exit rate constants (k1, k2) increase with decreasing DP:RP ratio and with decrease in quantity of MC, and quantity of SA, and the presence of dichloroethane (DCE) is preferred to chloroform (CF) as LM.
Desalination and Water Treatment, 2013
Desalination using liquid membranes (LMs) has been investigated in our laboratory using emulsion,... more Desalination using liquid membranes (LMs) has been investigated in our laboratory using emulsion, supported and flowing LMs. However, bulk liquid membranes (BLMs) have not yet been applied as is clear from the literature cited. Accordingly, in the present work, the aforementioned technique was investigated for removal of sodium chloride from solutions of different concentrations as an attempt for desalination. Variables investigated included: type and quantity of LM, quantity of mobile carrier (MC) in LM, and type and quantity of sequestering agent in receptor phase (RP). Results indicated that: a mixture of 1:1 b.v. dichloroethane (DCE) plus chlorobenzene (CB) was a better LM than CB alone, and that DCE was almost equivalent to nitrobenzene (NB). As to the effect of sequestering agent, soluble starch gave better complexation with NaCl than sorbitol in the RP. It was also shown that the presence of the selected MC was efficient. An optimum quantity of MC led to the highest percentage of extraction of NaCl. The smaller volume of LM leads to higher extraction due to shorter diffusion path of the complex of NaCl plus MC through the LM. The highest extraction obtained was about 75%.
Sustainability
Solar radiation is considered the main renewable energy source which reshapes the global sustaina... more Solar radiation is considered the main renewable energy source which reshapes the global sustainability plan for future development. Due to the lack of solar radiation measurements, this work investigates the performance of several temperature-based hybrid solar radiation models combining the parametric, statistical and satellite data approaches to estimate the global solar radiation on a horizontal surface. Over 35 years of meteorological data in the new location, Arar City, KSA (Latitude 30°96′ N and longitude 41°05′ E) are employed to establish and validate the models. These models are validated using two datasets with different averaging time spans to investigate the accuracy and reliability of different models as forecasting tools for the solar radiation. The mostly common statistical indicators are calculated to identify the most accurate model. The results show that Model (1) has the best performance among all models with high reliability as a solar radiation forecasting tool...
Water
Due to the impacts of water scarcity, the world is looking at all possible solutions for decreasi... more Due to the impacts of water scarcity, the world is looking at all possible solutions for decreasing the over-exploitation of finite freshwater resources. Wastewater is one of the most reliable and accessible water supplies. As the population expands, so do industrial, agricultural, and household operations in order to meet man’s enormous demands. These operations generate huge amounts of wastewater, which may be recovered and used for a variety of reasons. Conventional wastewater treatment techniques have had some success in treating effluents for discharge throughout the years. However, advances in wastewater treatment techniques are required to make treated wastewater suitable for industrial, agricultural, and household use. Diverse techniques for removing heavy metal ions from various water and wastewater sources have been described. These treatments can be categorized as adsorption, membrane, chemical, or electric. Membrane technology has been developed as a popular alternative ...
Case Studies in Thermal Engineering